OBJECTIVE: To evaluate nurses' perception regarding three different blood glucose control protocols for critically ill patients. METHODS: As part of a randomized trial comparing three blood glucose control protocols in critically ill patients (Computer-Assisted Insulin Protocol, Leuven Protocol, and conventional treatment), all nurses participating in the study were asked to fill in a questionnaire to assess their perceptions of efficacy, complexity, feasibility, and safety (as to the occurrence of hypoglycemic episodes), an to indicate which protocol they would like to see adopted as the standard one in the Intensive Care Unit they worked. RESULTS: Sixty nurses answered the questionnaires. Computer-Assisted Insulin Protocol was considered the most efficient protocol to maintain blood glucose levels within the target range by 58% of the nurses, compared to 22% for Leuven Protocol (p<0.001) and 40% for conventional treatment (p=0.04). Computer-Assisted Insulin Protocol was considered easier to use than Leuven Protocol (p<0.001) and as easy as conventional treatment (p=0.78). Out of the nurses, 37% considered Computer-Assisted Insulin Protocol more feasible than Leuven Protocol and conventional treatment. A total of 51% of nurses chose Leuven Protocol as the protocol more often associated with hypoglycemia, while 27% chose Computer-Assisted Insulin Protocol and 8% conventional treatment. Finally, 56% of the nurses selected Computer-Assisted Insulin Protocol as the protocol they would like to see adopted as the standard one in the Intensive Care Unit they were based, as compared to 22% that selected Leuven Protocol and 15% that selected conventional treatment. CONCLUSION: Computer-Assisted Insulin Protocol was considered more efficacious, easier to use and safer than Leuven Protocol by nurses. The complexity and feasibility of Computer-Assisted Insulin Protocol were considered similar to conventional treatment. Most nurses chose of Computer-Assisted Insulin Protocol as the protocol they would like to see adopted in their Intensive Care Units.